1. Field of the Invention
The present invention relates to a wire reciprocating device used to reciprocate a moving body, for example, such as a sliding door, a sunroof, a curtain, and a window glass of a vehicle, and specifically, relates to a biasing structure including a wire tensioner and a torsion spring.
2. Description of the Related Art
Some conventional devices to open and closed sliding door use a wire reciprocating device. In such a wire reciprocating device, a wire is wound around a pair of guide members disposed in front and rear portions of a side panel of a vehicle body. Both end portions of the wire are wound onto a reel drum in directions opposite to each other. The reel drum is attached to the side panel of the vehicle body between the both guide members. This reel drum is rotated forward and backward by driving means such as a motor to rotationally run and reciprocate the wire, so that the sliding door fixed in the middle of the wire is, reciprocated (for example, see Patent Literature 1).
In such a wire reciprocating device, while the reel drum is rotated forward or backward, a wound end portion of the wire is tensioned, and the other end portion unwound is loosened, which could cause slack. When such slack is caused, the slack portion of the wire could drop from guide means, and subsequent operations cannot be performed in some cases.
To prevent such slack, the conventional device is provided with a wire tensioner. In the wire tensioner, tension rollers are pressed onto the wire on both sides of the reel drum and biased in a direction orthogonal to the wire by means of separate tension springs.
Moreover, some conventional structures to bias the moving body by means of a torsion spring, for example, as shown in FIG. 1A, use a torsion spring 93 including a winding portion 90 and wire end extended portions 91 and 92 (for example, see Patent Literature 2). The winding portion 90 is formed by winding a center part of a wire material several times, and each of the wire end extended portions 91 and 92 is formed of an end portion of the wire extending from the winding portion 90 in the tangential direction. The winding portion 90 is fitted on the outside of a shaft 95 provided in a fixed member 94 and rotatably supported. The wire end extended portion 91 is brought into contact with an upper surface of a protruding piece 96 provided in the fixed member 94, and the other wire end extended portion 92 is brought into contact with an upper surface of a moving member 97 provided in the fixed member 94. Herein, the moving member 97 can move up and down within a rotation range thereof. The moving member 97 is thus biased downward by torsional restoring force of the winding portion 90 of the torsion spring 93.
In a lower portion of the moving member 97, a tension roller (not shown), for example, is rotatably supported. The tension roller is pressed onto a wire (not shown) configured to run rotationally and the like. The moving member 97 is thus used as a device to prevent sagging of the wire.
[Patent Literature 1] Japanese Patent Laid-open publication No. 11-91355
[Patent Literature 2] Japanese Patent Laid-open publication No. 6-137004